Coupler assembly

ABSTRACT

The present application describes a gooseneck coupler assembly that may include a gooseneck trailer pivot, an extension arm, and a pivot retention mechanism having a ball socket. The ball socket may engage with a hitch ball located on a towing vehicle. The gooseneck trailer pivot may be mounted on a towed vehicle or trailer and be capable of pivoting about a vertical axis relative to the trailer. During engagement, the ball socket and the extension arm may provide tilt capability but thereby prevent any rotational movement relative to the hitch ball. However, the gooseneck coupler assembly may still be able to tilt fore-and-aft or side-to-side relative to the hitch ball. Therefore, the only pivotal movement relative to a vertical axis would be permitted at the gooseneck trailer pivot.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/625,402, entitled “Coupler Assembly” filed on Sep. 24, 2012, which isa continuation of U.S. patent application Ser. No. 12/603,755, entitled“Coupler Assembly” filed on Oct. 22, 2009, which claims benefit fromU.S. Provisional Patent Application No. 61/196,983, entitled “CouplerAssembly,” filed on Oct. 22, 2008, all of which are hereby incorporatedin their entirety by reference.

FIELD OF INVENTION

The present invention is generally related to a hitch assembly and, moreparticularly, to a coupler assembly used for coupling a towed vehicle toa towing vehicle.

BACKGROUND

Many vehicles are designed to transport freight, goods, merchandise,personal property, and other such cargo. Often, a hitch assembly isutilized to connect a towed vehicle or trailer to a towing vehicle, suchas a truck for example, to increase the capacity to transport goods.Many types of coupling devices have been developed for providing thisconnection between a towing vehicle and a towed vehicle. Suchconnections may often include a shaft-mounted, ball-type hitch member,that may be conventionally referred to as a tow or hitch ball. The hitchball is generally attached to the towing vehicle, often in the flatbedof a truck, to permit connection to a trailer coupler. The trailertypically has a frame that extends outward so that the trailer may beattached to the towing vehicle. A trailer tongue is a portion of theframe that may extend beyond the trailer body.

Typically, the coupler may be attached to the tongue of the towedvehicle that may cooperate with the hitch ball to complete theconnection from the towed vehicle to towing vehicle. The trailer coupleroften has a socket portion that is sized and shaped to receive the hitchball. The hitch ball of the towing vehicle may be removably secured tothe trailer coupler to permit the towing vehicle to transport the towedvehicle, such as a trailer and its contents, boats, other vehicles,ATVs, furniture and other objects. The coupler thereby allows for thetrailer to pivot behind the towing vehicle. The socket to hitch ballconnection allows relative movement between the towing vehicle and thetrailer as the towing vehicle makes turns, traverses uneven or roughterrain, and passes along inclining and declining roadways.

There are many different types of trailer hitches. Some of the mostcommon types of hitches include gooseneck, fifth wheel, front mount, andothers. The gooseneck hitch may use a long, extended arm having acoupler attached to the lower end thereof. The gooseneck coupler mountedto the trailer may connects to the hitch ball installed in the bed ofthe towing vehicle. This system of coupling the trailer to the towingvehicle permits the towing vehicle to turn at sharper angles than arepermitted by a typical bumper hitch system. Often these gooseneckcouplers connect oversized trailers to towing vehicles having shortenedtruck beds. Such a connection configuration often leads to operationaldifficulties.

Many trailers are generally much larger and heavier than typicaltrailers and often require relatively heavy towing vehicles such asheavy-duty pickup trucks to pull them. Gooseneck trailer hitches areconsidered to be heavy duty and are often used to fasten trailersweighing 10,000 pounds or more. Gooseneck hitches are made toaccommodate things like horse trailers and other oddly shaped trailerswhose weight is not evenly distributed. A gooseneck trailer hitch isoften placed in the truck bed above the rear axle and the trailer isthen secured to it. The gooseneck hitch is much stronger than a regularball hitch and can haul much more weight.

Generally, a gooseneck coupler arm is mounted to the trailer at one endand has a socket at the other end that connects to the hitch ballinstalled in the bed of the towing vehicle. The gooseneck engages thehitch ball to pivotally engage the trailer to the towing vehicle. Thetrailer is thus able to pivot relative to the towing vehicle about avertical axis through the hitch ball to facilitate cornering andparking. Normally, the hitch ball is mounted directly over or a shortdistance in front of the rear axle of the towing vehicle in order tomaintain proper weight distribution. Thus, when the gooseneck couplerengages the hitch ball, a portion of the trailer's weight may be carrieddirectly over the rear axle of the towing vehicle. So as to permit theturning of the towing vehicle and relative pivoting between the towingvehicle and the trailer, there must be significant clearance between thepivot point and the rear of the towing vehicle cab in order to preventcontact between the trailer and the cab.

Recently, there has been a trend towards extending pickup truck cabs.These trucks have greatly expanded interior cargo volume and also havespecially designed rear jump seats for accommodating additionalpassengers. Unfortunately, most of these extended cab pickups are builton a standard wheelbase chassis because consumers prefer the drivingcharacteristics of a shorter truck, and accordingly, the beds of thesetrucks are typically six feet long rather than eight feet long. Althoughthese shorter bed pickups have the towing capacity to handle a heavytrailer, they do not have enough clearance between the axle and the rearof the cab to allow the trailer to pivot to a 90 degree angle withoutcontacting the cab, which could damage the truck or towing vehicle andseverely injure any occupants. In most circumstances, a trailer willcontact the cab of a short bed pickup at angles much less than 90degrees.

Therefore, there is a need in the art for an improved coupler assemblythat may offset the pivot connection between the hitch ball and thetrailer, such as by moving the pivot connection rearwardly. Further, sothat only one pivot connection is provided, the rotational movement ofthe gooseneck coupler relative to the hitch ball should be prevented.Therefore, moving the pivot position rearwardly of the couplerassembly's attachment point may enable a trailer to easily handle up toa 90 degree turn.

SUMMARY

A gooseneck coupler assembly is described herein. The gooseneck couplerassembly may include a gooseneck trailer pivot, an extension arm, and apivot retention mechanism having a ball socket. The ball socket mayengage with a hitch ball located on a towing vehicle. The goosenecktrailer pivot may be mounted on a towed vehicle or trailer and becapable of pivoting about a vertical axis relative to the trailer.During engagement, the ball socket and the extension arm may providetilt capability but thereby prevent any rotational movement relative tothe hitch ball. However, the gooseneck coupler assembly may still beable to tilt fore-and-aft or side-to-side relative to the hitch ball.Therefore, the only pivotal movement relative to a vertical axis wouldbe permitted at the gooseneck trailer pivot.

A coupler assembly may include a trailer pivot capable of engagementwith a towed vehicle, an extension arm attached to the trailer pivot,and a vehicle engagement member capable of selectively engaging a hitchball mounting aperture of a towing vehicle. The coupler assembly mayalso include an engaging device secured to the extension arm andattached to the vehicle engagement member, and a pivot retention memberengaged with the engaging member generally preventing rotation of thetowing vehicle relative to the extension arm.

A coupler assembly may include a trailer pivot capable of engagementwith a towed vehicle, an extension arm attached to the trailer pivot, avehicle engagement member capable of being mounted to a hitch ballmounting aperture of a towing vehicle, and an engaging device secured tothe extension arm and attached to the vehicle engagement member. Thecoupler assembly may also include a first pivot retention member engagedwith the engaging member generally preventing rotation of the towingvehicle relative to the extension arm, and a second pivot retentionmember attached to the vehicle engagement member and capable of engagingthe towing vehicle generally preventing rotation of the towing vehiclerelative to the extension arm.

A coupler assembly may include a trailer pivot capable of engagementwith a towed vehicle, and an extension arm attached to the trailer pivotand including a mounting block. The coupler assembly may also include amounting structure capable of being secured to a towing vehicle; themounting structure may include a universal joint, and a mounting body.

DESCRIPTION OF THE DRAWINGS

Objects and advantages together with the operation of the invention maybe better understood by reference to the following detailed descriptiontaken in connection with the following illustrations, wherein:

FIG. 1 illustrates a perspective view of a gooseneck coupler in anembodiment of the invention.

FIG. 2 illustrates a perspective view of the gooseneck coupler with aportion cut away.

FIG. 3 illustrates a front view of an embodiment of the gooseneckcoupler.

FIG. 4A illustrates a side view of an embodiment of the gooseneckcoupler.

FIG. 4B illustrates a side view of the gooseneck coupler.

FIG. 5 illustrates a perspective view of an embodiment of the gooseneckcoupler.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. It is to be understood that other embodiments may be utilizedand structural and functional changes may be made without departing fromthe respective scope of the invention. As such, the followingdescription is presented by way of illustration only and should notlimit in any way the various alternatives and modifications that may bemade to the illustrated embodiments and still be within the spirit andscope of the invention.

A gooseneck coupler assembly 10 is illustrated in FIGS. 1 through 5. Thecoupler assembly 10 is generally related to trailer 52 and hitchassemblies for use on towing vehicles 32 that may be used to tow largeor heavy towed vehicles. The coupler assembly 10 may be used for lockingout rotation about a vertical axis of the hitch ball 20 and providepivotal movement rearward of the hitch ball 20.

The coupler assembly 10 is intended to cover any mechanical means oflimiting or stopping the vertical rotation about the hitch ball 20 inconjunction with a secondary vertical pivot, such as at axis A (shown inFIGS. 2 and 5), that may be offset by some distance at the originaltrailer support, such as a Gooseneck or RV trailer. For example, thecoupler assembly 10 may be used in conjunction with a “Sidewinder”system produced and sold by Cequent.

The Sidewinder is a pin box coupler designed for short bed pickups thatmay eliminate turning and clearance issues so that a consumer may makeup to 90-degree turns without exiting the truck. Sidewinder's kingpinlocking mechanism moves the pivot position 20 inches rear of thecoupler's attachment point from the truck bed to the pin box under thenose of the trailer. This enables the Sidewinder to handle up to a90-degree turn. By moving the pivot rearward, the trailer tracks moreclosely to the tracks of the truck. This reduces the need for extra-wideturns and allows short bed pickups to jackknife with no fear of contact.

A gooseneck coupler assembly 10 may include a gooseneck trailer pivot12, an extension arm 14, and a pivot retention mechanism 18. Thegooseneck trailer pivot 12 may be positioned at any appropriate locationon the towed vehicle or trailer 52. For example, the gooseneck trailerpivot 12 may be mounted to the trailer 52 and may be capable of pivotingabout a vertical axis A relative to the trailer 52.

The extension arm 14 may be connected to the gooseneck trailer pivot 12by any appropriate means, such as with fasteners, welding, or the like.The extension arm 14 may extend outwardly from the gooseneck trailerpivot 12 and may be located at an end of the gooseneck trailer pivot 14.For example, the extension arm 14 may extend substantiallyperpendicularly or at any appropriate angle away from the goosenecktrailer pivot 12. The extension arm 14 may be of any appropriate shape,size, such as generally circular or tubular. The extension arm 14 may beof any appropriate length, such as the desired length to connect thetowed vehicle 52 to the towing vehicle 32.

The extension arm 14 may include a ball socket 16 (FIGS. 1-3). The ballsocket 16 may be integrally formed within the extension arm 14 or may bea separate component. The ball socket 16 may be positioned at anyappropriate location on the extension arm 14, such as at an end oppositethat of the gooseneck trailer pivot 12. The ball socket 16 may belocated at the end of the extension arm 14 forward of the trailer pivot12. The ball socket 16 may by of any appropriate shape or size, such asto receive a correspondingly shaped and sized hitch ball 20.

A hitch ball 20 may be mounted to a towing vehicle 32, such as the bedof a pickup truck. The hitch ball 20 may be mounted or secured to thetowing vehicle 32 by any appropriate means, such as those according tocommon industry practice. For example, the hitch ball 20 may be mountedwithin the bed of the towing vehicle 32 over the rear axle of the towingvehicle 32. The hitch ball 20 may then be secured to the frame of thetowing vehicle 32 through apertures (not shown) in the bed of the towingvehicle 32.

The ball socket 16 may engage the hitch ball 20. This engagement of theball socket 16 and hitch ball 20 may be referred to as a hitch ballassembly 36. As the ball socket 16 and hitch ball 20 are engaged, thegooseneck trailer pivot 12 may be secured to the towed vehicle ortrailer 52 and may be located rearwardly relative to the hitch ball 20.Traditionally, gooseneck trailers may have a vertical tube, such as around or square tube, welded to the front of the trailer 52 to support agooseneck coupler on an inner vertically adjustable tube. On round tubesystems, the extension arm 14 may be welded to the inner tube. Bushingsmay be used between the inner and outer tubes to facilitate rotation. Onsquare tube systems, an adapter with a rotational system may be added tothe bottom of the outer tube, then the extension arm 14 with trailerside rotation may be added to the side away from the trailer 52.

The coupler assembly 10 may maintain only one vertical pivot connectionbetween the hitch ball 20 and the towed vehicle 52 (see FIG. 1). Assuch, a pivot retention mechanism 18 may be provided to prevent therotation of ball socket 16 relative to the hitch ball 20 about avertical axis A (FIG. 2), while still allowing vertical rotation aboutaxis A at the trailer pivot 12.

The pivot retention mechanism 18 illustrated in FIGS. 1 and 2 mayinclude a pivot retention arm 22 and a support plate 24. The pivotretention arm 22 may be of any appropriate shape or size, such assubstantially rectangular, ovular or circular. The pivot retention arm22 may be connected near the socket 16 to provide engagement with thesupport plate 24. The pivot retention arm 22 may be a non-rotatingelement and may extend outwardly to engage the support plate 24.

The support plate 24 may be of any appropriate shape or size. Thesupport plate 24 may be secured to the towing vehicle 32 by anyappropriate means, such as with fasteners, welding, or the like. Thesupport plate 24 may be mounted to either the hitch ball assembly 36 orto the towing vehicle 32, such as on a platform 34 that may extend fromthe hitch ball 20 (FIGS. 4A and 4B). The support plate 24 may be locatedon or adjacent to the hitch ball assembly 36.

The support plate 24 may be located on any side of the hitch ball 20,such as the front, back, or either side, so long as it is lined up withthe center of the hitch ball 20 and allows the coupler assembly 10 toarticulate but not rotate. The key is for the non-rotating joint toallow articulation without rotation. The contact point or ball socket 16should remain on center with the hitch ball 20, preferably on the forand aft axis or side to side axis through the center of the hitch ball20.

The pivot retention mechanism 18 may include a retention pocket 28. Theretention pocket 28 may be positioned in any appropriate location, suchas in the support plate 24. The retention pocket 28 may be located inthe support plate 24 may include a lead in bevel or alignment opening 26to facilitate centering with the pivot retention arm 22 when the hitchball 20 is being coupled with the trailer 52.

The alignment opening 26 may be of any appropriate shape or size, suchas a generally angled shape transitioning from a wider opening to anarrower opening (FIGS. 1 and 3). The alignment opening 26 may guide thepivot retention arm 22 into a retention pocket or slot 28. The retentionpocket 28 may be of any appropriate shape or size, such as generallyrectangular or a vertical notch. The retention pocket 28 may becorrespondingly shaped and sized to receive the pivot retention arm 22.

The retention pocket 28 may be centered with the hitch ball 20, such asbeing mounted on center in any of the four axis located through thehitch ball 20. The retention pocket 28 and support plate 24 must be ableto resist rotational forces of the trailer 52 when turning or backingup. When the hitch ball 20 is coupled, the pivot retention arm 22 may belowered into and located within the retention pocket 28. This mayrestrict rotation when the coupler assembly 10 is latched.

During engagement, the alignment opening 26 may allow for adjustingmovement of the pivot retention arm 22 during hook up. The ball socket16 may have the pivot retention arm 22 extending outwardly from thecenter of the ball socket 16 to engage the vertical slot or retentionpocket 28. The alignment opening 26 may guide the retention arm 22 intoposition within the retention slot 28. Therefore, during engagement, theball socket 16 and the extension arm 14 may provide tilt capability butthereby prevent any rotational movement relative to the hitch ball 20.However, the gooseneck coupler 10 may still be able to tilt fore-and-aftor side-to-side relative to the hitch ball 20. Therefore, only pivotalor rotational movement relative to a vertical axis A would be permittedat the gooseneck trailer pivot 12.

The support plate 24 may be connected to the hitch ball assembly 36.Depending on the rotational resistance of the hitch ball assembly 36 ormounting structure 38, a pin 30, 46 may engage the bed of the towingvehicle 32 or a flat plate (not shown) may be bolted to the towingvehicle 32. As an alternative, there may be anti-rotational featureslocated where the hitch ball assembly 36 engages the gooseneck hitch.For example, a square shank and square hole coupler may be used. Asanother example, a round shank may have two off center pins (not shown)located in the bottom of the hitch ball 20 may engage the gooseneckhitch at the bottom of the hitch ball 20.

The coupler assembly 10 illustrated in FIGS. 4A and 4B may include asecondary pin 30. The secondary pin 30 may be of any appropriate shapeor size, such as generally circular or rectangular. The support platestructure 24 may be permanently attached to the bed of the towingvehicle 32 or may be attached to the hitch ball 20. The support plate 24may be spring biased and capable of pivoting during hookup to allow forengagement with the vertical retention pocket 28.

The pivot retention arm 22 may extend in any appropriate direction fromthe ball socket 16, such as at any 90 degree position relative to theposition shown in FIG. 1. Therefore, this coupler assembly 10configuration may substantially eliminate rotation about the verticalaxis at the hitch ball 20, while allowing for side-to-side andfore-and-aft pivoting as explained above.

As an alternative, a yoke (not shown) may be used in place of the hitchball 20. The yoke may have any appropriate number of points, such as athree way or a four way yoke. The four way yoke may allow forarticulation, but not rotation at the towing vehicle. At the other endof the extension arm 14, there may be a vertical pivot where the trailer52 may have a coupler, located six or more inches away from the cab ofthe towing vehicle 32 to provide extra clearance between the towingvehicle 32 and the towed vehicle 52.

The coupler assembly 10 illustrated in FIG. 5, may include a mountingstructure 38. The mounting structure 38 may be located within theflatbed of the towing vehicle 32. The mounting structure 38 may includea universal joint 40 and a mounting body 42. The universal joint 40 maybe of any appropriate shape or size, such as a substantially U-shape.The mounting body 42 may include a pin-receiving aperture 44. Thepin-receiving aperture 44 may be of any appropriate shape or size, suchas generally circular, rectangular or ovular.

The pin-receiving aperture 44 may permit the mounting structure 38 to beconnected to the frame of the towing vehicle 32. The mounting structure38 may be connected to the towing vehicle 32 by any appropriate means,such as with fasteners, welding or the like. For example, the mountingbody 42 may be located in a similar configuration and location as how ahitch ball 20 would be located.

The universal joint 40 may also include an anti-rotation pin 46. Theanti-rotation pin 46 may extend generally perpendicularly and outwardfrom the universal joint 40. The anti-rotation pin 46 may engage the bedand/or the frame of the towing vehicle 32 through an aperture (notshown) in the bed of the towing vehicle 32. The extension arm 14 mayinclude a mounting block 48 extending outwardly there from. The mountingstructure 38 may also include a mounting pin 50. The mounting pin 50 mayconnect the mounting block 48 to the universal joint 40 to provide tiltcapability but thereby preventing any rotational movement at themounting structure 38 in the towing vehicle. The tilt capability may before-and-aft or side-to-side. Therefore, only pivotal movement relativeto a vertical axis A would be permitted at the gooseneck trailer pivot12.

The coupler assembly 10 may provide for the ability to easily lock outrotation about a vertical axis of the hitch ball 20 and provide pivotalmovement rearward of the hitch ball 20. It may be important to have theextension arm 14 in line with the hitch ball 20 thereby permitting cleanarticulation at the hitch ball 20. By locking out vertical rotation atthe hitch ball 20, a second gooseneck trailer pivot point may be locatedsubstantially rearward. This second pivot point may allow the trailer 52to pivot about the vertical axis A behind the rear axle of the towingvehicle while the vertical loads of the system are maintained over orahead of the rear axle.

The coupler assembly 10 may provide for pivotal movement of the towedvehicle or trailer 52 rearwardly of the engagement point of the trailer52 to the towing vehicle 32. This may be further accomplished bypreventing rotation at the ball socket 16, and thereby the extension arm14, about a vertical axis relative to the hitch ball 20 so that only onepivot point is provided. Therefore, the gooseneck coupler assembly 10may allow the towed vehicle or trailer 52 to pivot relative to thetowing vehicle, such as about vertical axis A, during turningoperations.

Therefore, moving the pivot position rearwardly of the gooseneck couplerassembly's 10 attachment point would easily enable a trailer 52 tohandle up to a 90 degree turn effortlessly. By moving the pivotrearward, the trailer 52 may be able to track more closely to the tracksof the towing vehicle and thereby reduce the need for taking extra-wideturns. In addition, with the towing position of the gooseneck couplerassembly 10 locked in line with the towing vehicle, the consumer couldmake full use of the bed space in the towing vehicle, giving theconsumer extra storage.

Although the embodiments of the invention have been illustrated in theaccompanying drawings and described in the foregoing detaileddescription, it is to be understood that the invention is not to belimited to just the embodiments disclosed, but that the inventiondescribed herein is capable of numerous rearrangements, modificationsand substitutions without departing from the scope of the claimshereafter.

Having thus described the invention, we claim:
 1. A coupler assemblycomprising: a trailer pivot capable of engagement with a towed vehicle;an extension arm attached to the trailer pivot; a vehicle engagementmember capable of selectively engaging a hitch ball mounting aperture ofa towing vehicle; an engaging device secured to the extension arm andattached to the vehicle engagement member; and a pivot retention memberengaged with the engaging device generally preventing rotation of thetowing vehicle relative to the extension arm.
 2. The coupler assembly ofclaim 1, wherein the trailer pivot includes a generally vertical axiswhereby the towed vehicle may rotate relative to the vertical axis. 3.The coupler assembly of claim 2, wherein the towed vehicle is capable oftilting relative to towing vehicle at the vehicle engagement member. 4.The coupler assembly of claim 3, wherein the towed vehicle is capable oftilting fore and aft relative to the vertical axis at the vehicleengagement member.
 5. The coupler assembly of claim 1, wherein thevehicle engagement member includes a mounting body shaped and sized tobe secured to the hitch ball mounting aperture of the towing vehicle. 6.The coupler assembly of claim 5, wherein the engaging device includes amounting block and a generally U-shaped bracket attached to the mountingbody.
 7. The coupler assembly of claim 6, wherein the pivot retentionmember includes a mounting pin attached to the generally U-shapedbracket and engageable with the mounting block generally preventingrotation of the towing vehicle relative to the extension arm.
 8. Thecoupler assembly of claim 7, wherein the mounting pin prevents rotationabout a first vertical axis at the mounting body.
 9. The couplerassembly of claim 8, wherein the trailer pivot is capable of rotationabout a second vertical axis.
 10. The coupler assembly of claim 1,wherein the vehicle engagement member includes a socket attached to theextension arm and a hitch ball engaged with the socket and attached tothe hitch ball mounting aperture of the towing vehicle.
 11. The couplerassembly of claim 10, wherein the engaging device includes a retentionarm attached to the socket.
 12. The coupler assembly of claim 11,wherein the pivot retention member includes a support plate attached tothe towing vehicle.
 13. The coupler assembly of claim 12, wherein theretention arm is generally aligned with a center of the hitch ball. 14.The coupler assembly of claim 13, wherein the retention arm is capableof engaging the support plate.
 15. The coupler assembly of claim 14,wherein the support plate includes a retention pocket capable ofengaging the retention arm.
 16. A coupler assembly comprising: a trailerpivot capable of engagement with a towed vehicle; an extension armattached to the trailer pivot; a vehicle engagement member capable ofbeing mounted to a hitch ball mounting aperture of a towing vehicle; anengaging device secured to the extension arm and attached to the vehicleengagement member; a first pivot retention member engaged with theengaging member generally preventing rotation of the towing vehiclerelative to the extension arm; and a second pivot retention memberattached to the vehicle engagement member and capable of engaging thetowing vehicle generally preventing rotation of the towing vehiclerelative to the extension arm.
 17. The coupler assembly of claim 16,wherein the vehicle engagement member includes a platform and the secondpivot retention member includes a pin capable of engaging the towingvehicle.
 18. The coupler assembly of claim 17, wherein the vehicleengagement member includes a socket attached to the extension arm and ahitch ball attached to the platform and engaged with the socket.
 19. Thecoupler assembly of claim 17, wherein the vehicle engagement memberincludes a mounting body attached to the platform.
 20. A couplerassembly comprising: a towed vehicle engagement member configured toattach with a towed vehicle, wherein the towed vehicle is capable ofpivoting around a first vertical axis with respect to the towed vehicleengagement member; an extension arm extending from the engagementmember; a towing vehicle engagement member capable of coupling with atowing vehicle, the towing vehicle engagement member coupled with theextension arm; and an engaging member coupled with the vehicleengagement member generally preventing movement of the towing vehicleengagement member with respect to a second vertical axis relative to thetowing vehicle.
 21. The coupler assembly of claim 20, wherein the firstand second vertical axes are generally parallel.